kernel/resource.c

   1 /*
   2  *      linux/kernel/resource.c
   3  *
   4  * Copyright (C) 1999   Linus Torvalds
   5  * Copyright (C) 1999   Martin Mares <mj@ucw.cz>
   6  *
   7  * Arbitrary resource management.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/errno.h>
  12 #include <linux/ioport.h>
  13 #include <linux/init.h>
  14 #include <linux/malloc.h>
  15 #include <linux/spinlock.h>
  16 #include <asm/io.h>
  17
  18 struct resource ioport_resource = { "PCI IO", 0x0000, IO_SPACE_LIMIT, IORESOURCE_IO };
  19 struct resource iomem_resource = { "PCI mem", 0x00000000, 0xffffffff, IORESOURCE_MEM };
  20
  21 static rwlock_t resource_lock = RW_LOCK_UNLOCKED;
  22
  23 /*
  24  * This generates reports for /proc/ioports and /proc/iomem
  25  */
  26 static char * do_resource_list(struct resource *entry, const char *fmt, int offset, char *buf, char *end)
  27 {
  28         if (offset < 0)
  29                 offset = 0;
  30
  31         while (entry) {
  32                 const char *name = entry->name;
  33                 unsigned long from, to;
  34
  35                 if ((int) (end-buf) < 80)
  36                         return buf;
  37
  38                 from = entry->start;
  39                 to = entry->end;
  40                 if (!name)
  41                         name = "<BAD>";
  42
  43                 buf += sprintf(buf, fmt + offset, from, to, name);
  44                 if (entry->child)
  45                         buf = do_resource_list(entry->child, fmt, offset-2, buf, end);
  46                 entry = entry->sibling;
  47         }
  48
  49         return buf;
  50 }
  51
  52 int get_resource_list(struct resource *root, char *buf, int size)
  53 {
  54         char *fmt;
  55         int retval;
  56
  57         fmt = "        %08lx-%08lx : %s\n";
  58         if (root->end < 0x10000)
  59                 fmt = "        %04lx-%04lx : %s\n";
  60         read_lock(&resource_lock);
  61         retval = do_resource_list(root->child, fmt, 8, buf, buf + size) - buf;
  62         read_unlock(&resource_lock);
  63         return retval;
  64 }
  65
  66 /* Return the conflict entry if you can't request it */
  67 static struct resource * __request_resource(struct resource *root, struct resource *new)
  68 {
  69         unsigned long start = new->start;
  70         unsigned long end = new->end;
  71         struct resource *tmp, **p;
  72
  73         if (end < start)
  74                 return root;
  75         if (start < root->start)
  76                 return root;
  77         if (end > root->end)
  78                 return root;
  79         p = &root->child;
  80         for (;;) {
  81                 tmp = *p;
  82                 if (!tmp || tmp->start > end) {
  83                         new->sibling = tmp;
  84                         *p = new;
  85                         new->parent = root;
  86                         return NULL;
  87                 }
  88                 p = &tmp->sibling;
  89                 if (tmp->end < start)
  90                         continue;
  91                 return tmp;
  92         }
  93 }
  94
  95 static int __release_resource(struct resource *old)
  96 {
  97         struct resource *tmp, **p;
  98
  99         p = &old->parent->child;
 100         for (;;) {
 101                 tmp = *p;
 102                 if (!tmp)
 103                         break;
 104                 if (tmp == old) {
 105                         *p = tmp->sibling;
 106                         old->parent = NULL;
 107                         return 0;
 108                 }
 109                 p = &tmp->sibling;
 110         }
 111         return -EINVAL;
 112 }
 113
 114 int request_resource(struct resource *root, struct resource *new)
 115 {
 116         struct resource *conflict;
 117
 118         write_lock(&resource_lock);
 119         conflict = __request_resource(root, new);
 120         write_unlock(&resource_lock);
 121         return conflict ? -EBUSY : 0;
 122 }
 123
 124 int release_resource(struct resource *old)
 125 {
 126         int retval;
 127
 128         write_lock(&resource_lock);
 129         retval = __release_resource(old);
 130         write_unlock(&resource_lock);
 131         return retval;
 132 }
 133
 134 int check_resource(struct resource *root, unsigned long start, unsigned long len)
 135 {
 136         struct resource *conflict, tmp;
 137
 138         tmp.start = start;
 139         tmp.end = start + len - 1;
 140         write_lock(&resource_lock);
 141         conflict = __request_resource(root, &tmp);
 142         if (!conflict)
 143                 __release_resource(&tmp);
 144         write_unlock(&resource_lock);
 145         return conflict ? -EBUSY : 0;
 146 }
 147
 148 /*
 149  * Find empty slot in the resource tree given range and alignment.
 150  */
 151 static int find_resource(struct resource *root, struct resource *new,
 152                          unsigned long size,
 153                          unsigned long min, unsigned long max,
 154                          unsigned long align,
 155                          void (*alignf)(void *, struct resource *, unsigned long),
 156                          void *alignf_data)
 157 {
 158         struct resource *this = root->child;
 159
 160         new->start = root->start;
 161         for(;;) {
 162                 if (this)
 163                         new->end = this->start;
 164                 else
 165                         new->end = root->end;
 166                 if (new->start < min)
 167                         new->start = min;
 168                 if (new->end > max)
 169                         new->end = max;
 170                 new->start = (new->start + align - 1) & ~(align - 1);
 171                 if (alignf)
 172                         alignf(alignf_data, new, size);
 173                 if (new->start < new->end && new->end - new->start + 1 >= size) {
 174                         new->end = new->start + size - 1;
 175                         return 0;
 176                 }
 177                 if (!this)
 178                         break;
 179                 new->start = this->end + 1;
 180                 this = this->sibling;
 181         }
 182         return -EBUSY;
 183 }
 184
 185 /*
 186  * Allocate empty slot in the resource tree given range and alignment.
 187  */
 188 int allocate_resource(struct resource *root, struct resource *new,
 189                       unsigned long size,
 190                       unsigned long min, unsigned long max,
 191                       unsigned long align,
 192                       void (*alignf)(void *, struct resource *, unsigned long),
 193                       void *alignf_data)
 194 {
 195         int err;
 196
 197         write_lock(&resource_lock);
 198         err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
 199         if (err >= 0 && __request_resource(root, new))
 200                 err = -EBUSY;
 201         write_unlock(&resource_lock);
 202         return err;
 203 }
 204
 205 /*
 206  * This is compatibility stuff for IO resources.
 207  *
 208  * Note how this, unlike the above, knows about
 209  * the IO flag meanings (busy etc).
 210  *
 211  * Request-region creates a new busy region.
 212  *
 213  * Check-region returns non-zero if the area is already busy
 214  *
 215  * Release-region releases a matching busy region.
 216  */
 217 struct resource * __request_region(struct resource *parent, unsigned long start, unsigned long n, const char *name)
 218 {
 219         struct resource *res = kmalloc(sizeof(*res), GFP_KERNEL);
 220
 221         if (res) {
 222                 memset(res, 0, sizeof(*res));
 223                 res->name = name;
 224                 res->start = start;
 225                 res->end = start + n - 1;
 226                 res->flags = IORESOURCE_BUSY;
 227
 228                 write_lock(&resource_lock);
 229
 230                 for (;;) {
 231                         struct resource *conflict;
 232
 233                         conflict = __request_resource(parent, res);
 234                         if (!conflict)
 235                                 break;
 236                         if (conflict != parent) {
 237                                 parent = conflict;
 238                                 if (!(conflict->flags & IORESOURCE_BUSY))
 239                                         continue;
 240                         }
 241
 242                         /* Uhhuh, that didn't work out.. */
 243                         kfree(res);
 244                         res = NULL;
 245                         break;
 246                 }
 247                 write_unlock(&resource_lock);
 248         }
 249         return res;
 250 }
 251
 252 int __check_region(struct resource *parent, unsigned long start, unsigned long n)
 253 {
 254         struct resource * res;
 255
 256         res = __request_region(parent, start, n, "check-region");
 257         if (!res)
 258                 return -EBUSY;
 259
 260         release_resource(res);
 261         kfree(res);
 262         return 0;
 263 }
 264
 265 void __release_region(struct resource *parent, unsigned long start, unsigned long n)
 266 {
 267         struct resource **p;
 268         unsigned long end;
 269
 270         p = &parent->child;
 271         end = start + n - 1;
 272
 273         for (;;) {
 274                 struct resource *res = *p;
 275
 276                 if (!res)
 277                         break;
 278                 if (res->start <= start && res->end >= end) {
 279                         if (!(res->flags & IORESOURCE_BUSY)) {
 280                                 p = &res->child;
 281                                 continue;
 282                         }
 283                         if (res->start != start || res->end != end)
 284                                 break;
 285                         *p = res->sibling;
 286                         kfree(res);
 287                         return;
 288                 }
 289                 p = &res->sibling;
 290         }
 291         printk("Trying to free nonexistent resource <%08lx-%08lx>\n", start, end);
 292 }
 293
 294 /*
 295  * Called from init/main.c to reserve IO ports.
 296  */
 297 #define MAXRESERVE 4
 298 static int __init reserve_setup(char *str)
 299 {
 300         int opt = 2, io_start, io_num;
 301         static int reserved = 0;
 302         static struct resource reserve[MAXRESERVE];
 303
 304     while (opt==2) {
 305                 int x = reserved;
 306
 307         if (get_option (&str, &io_start) != 2) break;
 308         if (get_option (&str, &io_num)   == 0) break;
 309                 if (x < MAXRESERVE) {
 310                         struct resource *res = reserve + x;
 311                         res->name = "reserved";
 312                         res->start = io_start;
 313                         res->end = io_start + io_num - 1;
 314                         res->child = NULL;
 315                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
 316                                 reserved = x+1;
 317                 }
 318         }
 319         return 1;
 320 }
 321
 322 __setup("reserve=", reserve_setup);